magnetic field

(magnetic force as distributed over a space)

Astronomical bodies, including stars, planets,
galaxies can have magnetic fields, generally
generated by a dynamo, i.e., rotating
material that is electrically conductive.
They also be a remnant of earlier magnetism, preserved
by ferromagnetism, the "permanent magnet"
effect of iron and some other materials.

An object's magnetic field can be dipole, basically
arranged with the two magnetic polarities in
opposite directions, or multipole, arranged
so that more than one region of its surface
has each polarity. The dynamo includes moving
material conducting electricity, e.g., something
conductive convecting. A body (planet or star)
showing a dipole field suggests the magnetic
field's origin is largely the product of
a single large dynamo or aligned dynamos.
A multipole field may be the result of
ferromagnetism generated at an earlier age,
or may be multiple misaligned dynamos.
The latter is more likely in larger bodies
and in slower rotation.
A magnetic field can be "basically" dipole,
i.e., include only small, weak regions other
than what is expected in a dipole.
Jupiter has a dipole field, but also magnetic spots,
which might share characteristics of sunspots.

An angular power spectrum of the magnetic field strength
(a magnetic power spectrum, using power in the sense of
"the square of the multipole expansion coefficients")
around a spherical magnetized object (or sphere-shaped
surface concentric with the center of an object)
yields a characteristic of the
field, e.g., to what degree it is organized into multiple
poles at various scales.

There is a tendency to align a body's magnetic
field with its spin, but it can be off,
often by several degrees, a dipole tilt.
Some cited solar system magnetic fields
(sources I've found are not always consistent):

Io, Europa, Callisto, and Titan have basically none.
The Sun's varies over its 22-year cycle during which it flips polarity
twice.
Its topology varies, more dipole-like during solar minimum
(fewest sunspots),
the tilt for most of the cycle is 10° or less,
and its magnetic flux density is on the order of 100 times Earth's.

Current models and simulations produces some of the features seen
in solar system magnetic fields, but have not been made to
consistently reproduce them in detail.